An example of a prior art pressure transducer using strain gauge technology of the type with which the invention is concerned is disclosed and claimed in U.S. Pat. No. 6,742,395, which issued Jun. 1, 2004 to the assignee of the present invention, the subject matter of which is incorporated herein by this reference. In that patent, a transducer is described having a tubular port fitting formed with a fluid receiving opening at one end and a closed, integrally formed diaphragm at an opposite end. A support member having an apertured flat end wall is locked onto the pedestal end in a selected orientation with the aperture aligned with strain gauge sensor elements bonded to the diaphragm. A circuit board is mounted on the support member and mounts electronic components for conditioning and amplifying sensor signals. Wires are bonded both to the strain gauge sense elements and to circuit board pads on the circuit board and then encapsulated by silicone gel.
A cover, attachable to the support member is used to mount helical spring contact members to position them for engagement with landing zones of the circuit board. The helical spring contact members are enclosed within longitudinally extending cavities in the cover aligned with the landing zones when the cover is attached to the support member. An elastomer environmental O-ring seal or gasket member is received in a circumferential groove in the surface of the cover. A generally cup-shaped EMC shield is disposed in a chamber formed on a side of the cover facing the circuit board, the shield provided with tabs which extend outwardly through openings in the side-wall of the cover beyond the outer periphery of the side-wall. The cover is locked onto the support member and the helical spring contact members, received in the longitudinal cavities in the cover, have one end protruding from the cover. A combined electrical connector and hexagonal metal housing member is disposed over the cover. The connector has bent portions of terminals acting as contact landing zones for electrical connection with the helical contact spring members that protrude from the cover member to electrically connect the terminals to the circuit board landing zones. The EMC shield tabs are spring biased into electrical connection with the metal housing member. The housing member and connector apply a selected load to the elastomer gasket member, the housing being welded around its lower periphery to a support flange attached to the port fitting to form a fluid seal and to maintain the selected loading on the elastomer gasket member.
Transducers made in accordance with the noted patent are highly effective and are widely used; however, they are not suitable for use with high temperature fluids, for example fluids at temperatures of up to 180 degrees C.